Propargyl sulfide as a corrosion inhibitor in acidic solutions



United States Patent PROPARGYL SULFIDE AS A CORROSION INHIBI- TOR IN ACIDIC SOLUTIONS Gerald L. Foster and Billy D. Oakes, 'lhrlsa, Okla asslgnors to The Dow Chemical Company, Midland, Mich, a corporation of Delaware No Drawing. Application September 10, 1956 Serial No. 608,716

2 Claims. (Cl. 252-395) This invention relates to a new compound, propargyl sulfide, and to its use in inhibiting the acid corrosion of ferrous metals.

An object of this invention is to provide, as new compositions of matter, propargyl sulfide, corrosion inhibitors comprising propargyl sulfide, and acidic solutions inhibited against the corrosion of metals comprising propargyl sulfide.

A particular use for which propargyl sulfide is outstanding is as a corrosion inhibitor for use in aqueous acids for the protection of ferrous metals. As a corrosion inhibitor, it is efiective in aqueous non-oxidizing acids, including H 80 HCl, H,P0 CH,CO0H and the like. By aqueous acid we mean acid in the presence of water and do not mean to exclude the presence of other substances. For such use, only a very small amount of the sulfide is needed. As little as a few thousandths of one percent in an acid solution is suficient to reduce significantly the rate at which ferrous metals in contact with the solution are corroded.

The practice of the invention is illustrated by the following examples.

EXAMPLE I.--PREPARA'I'ION 0F PROPARGYL suu ma Two moles of KSH were prepared by dissolving 2 m. of KOH (112 g.) in 150 ml. of water and bubbling H S into the solution until saturated. This solution was slowly added to 2 m. of propargyl bromide. The heat of reaction was sufiicient to bring the mixture to the boiling point, after which heat was applied to. maintain reflux for 2 hrs. The KBrformed was filtered out (67 percent yield), after which the organic layer was separated, dried and distilled under reduced pressure such that it distilled at room temperature. In this way a water-white product having the characteristic odor of sulfides was obtained. The yield of sulfide was slightly lower than that of Hit because of the formation of a polymeric residue. It had B.P., 72 to 74' C. at 32 mm., u 1.521, and speclfie gravity, 1.005 at 25' C. The carbon, hydrogen; sulfur analysis showed:

semi Theoretical u sass tau 8 s 3 siii EXAMPLE IIQ-PROPARGYL SULFIDE AS A CORROSION INHIBITOR of metal removed by corrosion. Some typical results thus obtained are shown in the following tables.

hrs. the coupons were removed, washed, dried, and weighed to determine the amount Patented Mar. 31, 1959 Corrosion Rate lbs.

zt/dsy M Sulfide, percent Table II EEIECT OF TEMPERATURE AND ACID CONCENTRATION N CORROSION INHIBITION BY 0.4 PERCENT OF PRO- PARGYL BULFIDE IN H01 I cm is aft? 1M7 All)? .(Illd Tunnel-store, I.

,The elfectiveness of propargyl sulfide in inhibiting corrosion by various acids at room temperature is illustrated in Table III.

7 mu m CORROSION RATE! OF VARIOUS ACIDS AT 5 PERCENT CONCENTRATION WITH AND WITHOUT OR INHIBI omn am,

. Acid lbJltl. MW

no.1 Will-'10..

Other non-oxidizing acids are inhibited by ptopargyl sulfide similarly to those shown in Table III. Likewise, othertypesofsteel,ironand-fetronsmetalsarepr0- tected from corrosion by aqueous non-oxidizing acids vp p svl lfi e- We claim:

0.00m .oomo Ioooor 999999 morn-s9 for, propargyl sulfide.

2.Acompositionasinclalm1whesein dis hydrochloricaci. than! Isles-ere Glad in the file of thh patssa Uni-ran sra'ras PATENTS 2,101,114 Conklin et al. my s, 1955 "ass 

1. A COMPOSITION CONSISTING ESSENTIALLY OF AN AQUEOUS NON-OXIDIZING ACID AND, AS A CORROSION INHIBITOR THEREFOR, PROPARGYL SULFIDE. 